Question

In a tank full of water, the pressure on a surface 2 meters below the water level is 1.5 kPA. What's the pressure on a surface 6 meters below the water level ?

Answer 1

Answer:

P = 40.7kPa

Explanation:

To find the pressure on a surface 6 meter below you use the following formula, which takes into account the heights in which pressures are measured and also the density of the fluid and the gravitational acceleration:

$P_2-P_1=-\rho g(y_2-y_1)$             (1)

P2: pressure for a height of -6 m = ?

P1: pressure for a height of -2 m = 1.5kPa = 1500 Pa

ρ: density of water = 1000kg/m^3

g: gravitational acceleration = 9.8 ms^2

y2: -6m

y1: -2m

(the height is measure from the water level, because of that, the heights are negative)

You solve the equation (1) for P1:

$P_1=P_2-\rho g(y_2-y_1)$         (2)

Next, you replace the values of all variables in equation (2):

$P_2=1500Pa-(1000kg/m^3)(9.8m/s^2)(-6-(-2))m=40700Pa\\\\P_2=40.7kPa$

hence, the pressure on a surface 6 m below the water level is 40.7kPa